A Seattle woman with a sinus infection tragically died after contracting rare brain-eating amoeba.

The 69-year-old woman first developed a persistent sinus infection, which led doctors to prescribe her with a commonly-used neti pot to flush out her sinuses, according to a case report published in September’s International Journal of Infectious Diseases.

Instead of using sterile water or saline, both of which are recommended when using a neti pot, the woman reportedly rinsed her nose with tap water filtered from a Brita Water Purifier, the case report said.

After using the unsterilized water to rinse her sinuses for a month, she reportedly developed a rash on the bridge of her nose and raw skin near her nostrils, originally believed to be a skin condition called rosacea.

When the rash didn’t go away, even after several visits to a dermatologist and biopsies, doctors became perplexed at her mysterious health dilemma.

Things got worse for the woman a year after the rash first emerged when she had a seizure. According to the report, the woman never lost consciousness but was unable to cognitively function and was shaking on the left side of her body.

She finally underwent a CT scan where the woman learned she had a 1.5-centimeter lesion on her brain, the report said. Doctors initially believed that it was a tumor, due in part to the fact that breast cancer reportedly ran in the woman’s family.

But they soon learned, upon operating, that the mass held dead brain tissue making the diagnosis even more difficult. The medical team then took a sample of the mass and send it to neuropathologists at Johns Hopkins University for further analysis.

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From there, the woman’s condition began to deteriorate, as the team at Johns Hopkins suggested that the mass seemed to be a possible amoebic infection. She was immediately admitted for another surgery to remove the brain mass, where doctors noted “clear evidence of amoebic infection and dramatic hemorrhagic necrosis.”

“Despite aggressive anti-amoebic therapy, the patient’s condition continued to deteriorate,” the report says. “Within 1 week she was more somnolent and then became comatose… At this point, the family decided to withdraw support.”

After the woman had died, lab results revealed that her infection on her brain tissue and nose rash were from an amoeba called Balamuthia mandrillaris.

According to the Centers for Disease Control and Prevention (CDC), Balamuthia was first discovered in 1986 and has since been reported in about 200 cases worldwide, with 70 confirmed cases in the United States.

B. mandrillaris, which was described in the report as “extremely unusual” and “uniformly fatal,” is reportedly very difficult to detect and learn about because of its resemblance to other cells and tumors. The CDC even notes that the infection is so uncommon, “it is possible that there have been additional cases that were misdiagnosed.”

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Senior case report author Dr. Charles Cobbs, who is a neurosurgeon at the Swedish Medical Center in Seattle, told LiveScience that he suspects the woman contracted the fatal infection from using the unsterilized water in her neti pot as the amoeba could have been in the tap water.

“It’s so exceedingly rare that I’d never heard of it,” Cobbs told the outlet.

A representative for Brita did not immediately respond to PEOPLE’s request for comment.

Currently, the CDC says there are no known ways to prevent the infection due to its mysterious nature of contraction.

While the case seems incredibly terrifying, as so much of it was unknown, Cobbs stressed one major thing for those who use neti pots and are concerned moving forward. “People should just go about their normal lives,” he told LiveScience. But when using the nasal rinser, “definitely use sterile water or saline.”